Bug 42463

Summary:

[Qt] Avoid QImage::pixel() in getImageData()

Product:

WebKit

Reporter:

Andreas Kling <kling>

Component:

WebCore Misc.

Assignee:

QtWebKit Unassigned <webkit-qt-unassigned>

Status:

RESOLVED FIXED

Severity:

Normal

Keywords:

Performance, Qt, QtTriaged

Priority:

Version:

528+ (Nightly build)

Hardware:

All

OS:

All

Attachments:

Description	Flags
Proposed patch	none
Proposed patch v2	none

Description Andreas Kling 2010-07-16 09:36:18 PDT

From the QImage documentation:
Warning: This function is expensive when used for massive pixel manipulations.

We should use scanLine() (or even better in Qt 4.7, constScanLine()) instead.

Comment 1 Andreas Kling 2010-07-16 09:38:02 PDT

Created attachment 61817 [details]
Proposed patch

Comment 2 Andreas Kling 2010-07-16 09:38:53 PDT

This change yields a 1% speedup on http://mrdoob.com/lab/javascript/effects/plane_deformations/

Comment 3 Andreas Kling 2010-07-16 13:01:48 PDT

Created attachment 61840 [details]
Proposed patch v2

Oops, don't use QRgb* to traverse the scan lines, since QRgb might be 64-bit. Use quint32* instead.

Comment 4 Andreas Kling 2010-07-19 05:45:58 PDT

Comment on attachment 61840 [details]
Proposed patch v2

Clearing flags on attachment: 61840

Committed r63652: <http://trac.webkit.org/changeset/63652>

Comment 5 Andreas Kling 2010-07-19 05:46:08 PDT

All reviewed patches have been landed.  Closing bug.